[PATCH 2/3] powermac: proper time of day after resume

[Johannes Berg]

On Wed, 2007-01-24 at 17:34 +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2006-12-13 at 13:38 +0100, Johannes Berg wrote:
> > plain text document attachment (time-resume.patch)
> > This patch converts the time restore code from a PMU notifier to a regular
> > sys device so I can profit from it even when I don't suspend through the
> > PMU, i.e. suspend to disk.
> > 
> > Also another step towards dropping pmu_sleep_notifier completely.
> 
> I'd rather do it differently: On suspend, read the RTC and save the
> value. On resume, read it again, diff the values, and add that to the
> current time.

Alright, how about something like this? I still need to fill in the
actual calculations of course :)

--- mb-wireless.orig/arch/powerpc/platforms/powermac/time.c	2007-01-25 14:09:12.288927117 +0100
+++ mb-wireless/arch/powerpc/platforms/powermac/time.c	2007-01-26 14:16:18.598954773 +0100
@@ -297,49 +297,11 @@ int __init via_calibrate_decr(void)
 }
 #endif
 
-#ifdef CONFIG_PM
-/*
- * Reset the time after a sleep.
- */
-static int
-time_sleep_notify(struct pmu_sleep_notifier *self, int when)
-{
-	static unsigned long time_diff;
-	unsigned long flags;
-	unsigned long seq;
-	struct timespec tv;
-
-	switch (when) {
-	case PBOOK_SLEEP_NOW:
-		do {
-			seq = read_seqbegin_irqsave(&xtime_lock, flags);
-			time_diff = xtime.tv_sec - pmac_get_boot_time();
-		} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-		break;
-	case PBOOK_WAKE:
-		tv.tv_sec = pmac_get_boot_time() + time_diff;
-		tv.tv_nsec = 0;
-		do_settimeofday(&tv);
-		break;
-	}
-	return PBOOK_SLEEP_OK;
-}
-
-static struct pmu_sleep_notifier time_sleep_notifier = {
-	time_sleep_notify, SLEEP_LEVEL_MISC,
-};
-#endif /* CONFIG_PM */
-
 /*
  * Query the OF and get the decr frequency.
  */
 void __init pmac_calibrate_decr(void)
 {
-#if defined(CONFIG_PM) && defined(CONFIG_ADB_PMU)
-	/* XXX why here? */
-	pmu_register_sleep_notifier(&time_sleep_notifier);
-#endif
-
 	generic_calibrate_decr();
 
 #ifdef CONFIG_PPC32
--- mb-wireless.orig/arch/powerpc/kernel/Makefile	2007-01-26 14:16:35.838954773 +0100
+++ mb-wireless/arch/powerpc/kernel/Makefile	2007-01-26 14:16:47.918954773 +0100
@@ -50,6 +50,7 @@ extra-y				+= vmlinux.lds
 
 obj-y				+= time.o prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o
+obj-$(CONFIG_PM)		+= time_suspend.o
 obj-$(CONFIG_PPC32)		+= entry_32.o setup_32.o misc_32.o
 obj-$(CONFIG_PPC64)		+= misc_64.o dma_64.o iommu.o
 obj-$(CONFIG_PPC_MULTIPLATFORM)	+= prom_init.o
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ mb-wireless/arch/powerpc/kernel/time_suspend.c	2007-01-26 15:33:55.879025345 +0100
@@ -0,0 +1,62 @@
+/*
+ * Common code to keep time when machine suspends.
+ *
+ * Copyright 2007	Johannes Berg <johannes at sipsolutions.net>
+ *
+ * GPLv2
+ */
+
+#include <linux/time.h>
+#include <asm/rtc.h>
+
+static struct rtc_time suspend_rtc_time;
+
+/*
+ * Reset the time after a sleep.
+ */
+static int timer_resume(struct sys_device *dev)
+{
+	struct timespec tv;
+	struct rtc_time cur_rtc_time;
+
+
+	get_rtc_time(&suspend_rtc_time);
+
+	do_gettimeofday(&tv);
+
+	/* FIXME: do something with tv here */
+
+	do_settimeofday(&tv);
+
+	return 0;
+}
+
+static int timer_suspend(struct sys_device *dev, pm_message_t state)
+{
+	WARN_ON(!ppc_md.get_rtc_time);
+
+	get_rtc_time(&suspend_rtc_time);
+
+	return 0;
+}
+
+static struct sysdev_class timer_sysclass = {
+	.resume = timer_resume,
+	.suspend = timer_suspend,
+	set_kset_name("timer"),
+};
+
+static struct sys_device device_timer = {
+	.id = 0,
+	.cls = &timer_sysclass,
+};
+
+static int time_init_device(void)
+{
+	int error = sysdev_class_register(&timer_sysclass);
+	if (!error)
+		error = sysdev_register(&device_timer);
+	return error;
+}
+
+device_initcall(time_init_device);

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